4 NINETEENTH REPORT STATE ENTOMOLOGIST OF MINNESOTA—I1Q22 
of states much farther south. The usual rigors of our northern winters 
and the shortness of our summers prevent many insects from becoming 
very serious pests. If 1921-22 had been similar to 1920-21 the great 
increase of virulence noted in the summer of 1921 would have reached 
serious proportions in 1922. Fortunately the last season returned to 
normal and no unusual outbreak occurred. 
Corn Ear Worm (Heliothis obsoleta Fabr.) 
In 1921 the damage done by the corn ear worm was very severe. 
Ordinarily this insect is not a bad pest in Minnesota. In our expert- 
mental plot where corn has been grown in some part each year for 
seven years, the ears infested have rarely been more than 10 per cent 
and usually 5 per cent or less. In 1921 the injury reached 20 per 
cent and in some parts of the state much more. Field corn, altho 
normally not injured, was seriously damaged. In some cases even the 
tassels were attacked before they opened. 
The reason for this marked increase in 1921 was probably as 
follows: The insect passes the winter as a pupa in the soil and accord- 
ing to our experiments, comparatively few survive in Minnesota. Our 
infestation comes from moths which fly in from states to the south. 
Whether in the winter of 1920-21 more of these pupae survived the 
winter or whether more survived the winter in neighboring states, or 
whether the moths, on account of the warm spring, were able to start 
operations earlier, there was a decided increase which may be accounted 
for in one of the ways mentioned. In the summer of 1922 the corn 
ear worm infestation was only slightly higher than normal and was 
less than 10 per cent in Golden Bantam. The insect will probably not 
be serious in 1923. 
Unfortunately, no good method for controlling this insect in field 
corn has yet, been found. Cultivating the soil as much as possible 
after harvest, particularly fall plowing, will help. In small fields of 
sweet corn we have controlled the pest by dusting arsenate of lead 
directly on the fresh silks, at short intervals over a period of two 
weeks. ‘ Experimenters in other states have obtained similar results. 
Granary Weevil (Calendra granaria Linn. ) 
The insects which attack stored grain were unusually destructive 
in 1921. The granary weevil, which hitherto had been unknown in 
Minnesota spring wheat, was prevalent throughout the southwestern 
part of the state. Its general distribution in elevators and granaries 
can be accounted for only by the mild winter followed by a long warm 
summer. The damage done by the granary weevil was added to by 
